1. Field of the Invention
The present invention relates to method and apparatus for recording and reproducing video and other broadband signals, and more particularly to method and apparatus for recording and reproducing such signals on a magnetic recording disc or the like with good fidelity, high signal strength, and long disc life.
2. Description of the Prior Art
Electromagnetic transducer heads for video recording operation in contact with a moving magnetic recording disc, sometimes called "contact video heads", are well known in the prior art. The contact video heads of the prior art have in general been so massive or required such high head pressures, or both, that they have been characterized by very short service life, or have abraded and destroyed their associated recording surfaces in a short time, or both. For contact video recording, the contact heads of the prior art have made it necessary to use only recording discs in which a wear protecting layer overlies the magnetizable material in which the video information is stored. As is well known, such wear protecting layers reduce the strength of the signal which can be recorded on and reproduced from the recording disc; particularly when, as is sometimes the case, such layers approximate to the recording head gap width in thickness. In addition, as is known in the art, organic protective layers may decrease the planarity of the recording surface as compared with the planarity of the uncoated disc, and thus worsen the problem of tracking by the contact video head. Yet further it is also known in the art that such protective layers sometimes wear off as a powder, which, to cite but one problem created thereby, may adhere to the contact face of the head and even further increase the gap between the head and the magnetic recording layer. Finally, the heat necessary to produce oxide protective layers sometimes warps or otherwise damages the disc. As an additional prior art disadvantage, it is noted that the sled bodies of most if not all of the contact video recording heads of the prior art have been flat plates or the like of such large area as to experience severe buffeting due to the air turbulence produced by the moving surface of the recording disc, resulting in seriously shortened recording disc life, head damage, or both.